Testis length distinguishes haploid from diploid drones in Melipona quadrifasciata (Hymenoptera: Meliponinae) Mara Garcia Tavares, André Southernman Teixeira Irsigler and Lucio Antonio De Oliveira Campos Apidologie, 34 5 (2003) 449-455 DOI: 10.1051/apido:2003045